The field of child resistant cap and tube assemblies, which carry medicines, vitamins and the like, have become of major importance and interest in the pharmaceutical industry. There is a growing need for container assemblies that are difficult for children to open, particularly accidentally. Also, increased interest is being shown in cap and tube assemblies which cannot be opened by happenstance but which require a specific and positive step to be taken in order to have access to the contents. This is particularly true when medicines, vitamins and topical treatments such as eye drops are contained in such tubes.
In prior art devices, designs have been proposed which include a three piece construction where a tube body contains a plug attached to a portion of the main body of the tube. The wall of the tube has been weakened sufficiently to permit the plug to be torn from the tube. A cap portion is designed so that one end might be fitted over the tube having the plug, thereby protecting the plug and tube. The other end is then designed to interact with the plug in a twisting manner to remove the plug by rupturing the thin wall of the tube to which the plug is attached. This design has not been effective, however, because of the additional concern caused by the existence of the plug and the need for safe and reliable disposal of the plug.
In my prior U.S. Pat. No. 4,867,326, I have developed a child-resistant cap and tube assembly which has a high reliability in pass/fail inspection opportunities. This design permits easy inspection of unit dose sterile medicaments which do not contain preservatives in the product, to avoid use of spoiled or contaminated products.
My prior device has a tube which has one end portion which terminates in an axially centered first opened surface at the outer perimeter of the end portion. Recessed below the surface of the end portion is a thin wall which seals the tube. The tube has a second surface, called a surface of interference, which operates to interfere with axial movement on the end portion. The cap has a resistance surface which interengages the end to locate the cap at a first position where a thin wall portion on the tube is protected. Movement overcoming the restraining efforts of the two surfaces causes a puncture means to move to then puncture the thin wall and provide access to the contents.
One of the difficulties with the prior device in my U.S. Pat. No. 4,867,326 is not that it is not effective. Rather, it has been highly effective in keeping children and others from inadvertently opening the container and causing loss or damage to the contents. It is also suitable for a pass/fail inspection step as the thin wall is clearly visible when the cap is removed. If it appears to have been punctured, the contents or the condition of the thin wall will make that fact easily determined.
One of the features of my prior U.S. Pat. No. 4,867,326 is that the package looks substantially the same before and after activation. This is an appealing appearance but is not suitable in those situations when it is necessary to determine whether or not there has been activation by the mere glance of the eye. In other words, it is not possible to tell at a glance if the child-resistant feature has been overcome in some manner. Accordingly, it is an object of this invention to provide a device which is capable of providing not only child-resistance but also a quick visual warning or sign that the device has in fact been opened.
As is true in any system where axial force is the primary direction in which a system operates, there is another way in which my system described in my U.S. Pat. No. 4,867,326 can be improved. In my prior system, axial activation force was all that was needed to overcome, abeit with substantial force, the interengagement of the resistance surface and the surface of interference. Once this takes place, for whatever reason, the piercer moves to the second position as described in that patent and the thin wall seal which has been protecting the contents is pierced. That is desirable only when the user makes that decision and not merely because the force has been overcome inadvertently. It is therefore another object of this invention to provide a child-resistant tube and cap assembly that requires more than axial force to provide access to the contents. At the same time, it is an object of this invention to provide a device which retains the simple and very effective axial activation system of my U.S. Pat. No. 4,867,326. Thus it is an object of this invention to have the best of my prior design while adding additional features of value.
There is another concern that has become important in the child-resistant container industry, and that is the desire that a conscious mental step be needed in order to move the cap and tube into alignment for activation, and that they are somehow not capable of activation without that conscious step. Stated another way, it is an object of this invention to provide a device which is sufficiently complex to prevent random activity from putting the device in a condition for being activated.
Other objects will appear hereinafter.